float sphere_intersect(vec3 center, float radius, const ray& ray, const range &r)
{
if(keep_stats) sphere_intersections++;
vec3 diff = vec3_subtract(ray.o, center);
float b = 2 * vec3_dot(ray.d, diff);
float radicand = b * b - 4 * (vec3_dot(diff, diff) - radius * radius);
if(radicand < 0)
return NO_t;
float t1 = (-b + sqrtf(radicand)) / 2;
if(t1 < r.t0)
return NO_t;
float t0 = (-b - sqrtf(radicand)) / 2;
if(t0 > r.t1)
return NO_t;
if(t0 < r.t0)
return t1;
return t0;
}
/**
* Component of the support function for a cylinder collider.
**/
static void
object_support_component_cylinder(object_t *object,
float direction[3], float out[3])
{
float top[3] = { 0, object->h / 2, 0 };
float bottom[3] = { 0, -object->h / 2, 0 };
float axis[3];
float dir_perp[3];
float trans[16];
float dot_top;
object_get_transform_mat(object, trans);
/* Top and bottom are set to points in the middle of the top and the
* bottom faces of the cylinder respectively. We transform them to
* their worldspace positions.
*/
matrix_vec3_mul(trans, top, 1.0, top);
matrix_vec3_mul(trans, bottom, 1.0, bottom);
/* We get an axis vector that runs down the middle of the cylinder. */
vec3_subtract(top, bottom, axis);
/* Part of another process, but useful now for a reason... */
vec3_cross(axis, direction, dir_perp);
/* If the cross product is zero, our direction is aligned with the
* cylinder and top and bottom are our two final candidates.
*/
if (vec3_magnitude(dir_perp) > 0) {
/* This completes what we started with the last cross product.
* dir_perp is now a vector perpendicular to the cylinder's
* axis, but as close to our selected direction as possible.
*/
vec3_cross(dir_perp, axis, dir_perp);
/* Scale dir_perp to be the radius of our cylinder.
*/
vec3_normalize(dir_perp, dir_perp);
vec3_scale(dir_perp, dir_perp, object->r);
/* Finally, move top and bottom to the edges of our cylinder in
* the appropriate direction. We now have our two final
* candidates.
*/
vec3_add(dir_perp, top, top);
vec3_add(dir_perp, bottom, bottom);
}
/* We now have two candidates, top and bottom. We can just use largest
* dot product to determine which is furthest.
*/
dot_top = vec3_dot(top, direction);
if (dot_top > vec3_dot(bottom, direction))
memcpy(out, top, 3 * sizeof(float));
else
memcpy(out, bottom, 3 * sizeof(float));
}
static void find_nearest_block(struct group *group, struct ray const *ray, struct nearest *nearest)
{
struct groupdata *groupdata = group->data;
struct ray groupspaceray;
vec3_subtract(&groupspaceray.origin, &ray->origin, &group->position);
groupspaceray.direction = ray->direction;
buffer *buffer = create_buffer();
ptrarray *blocks = groupdata->blocks;
size_t blockcount = ptrarray_count(blocks);
for (size_t i = 0; i < blockcount; ++i)
{
block *block = get_ptrarray(blocks, i);
get_block_triangles(block, buffer);
triangle *tris = buffer_data(buffer);
size_t tricount = buffer_count(buffer, sizeof(struct triangle));
for (size_t j = 0; j < tricount; ++j)
{
float temp;
if (ray_intersect_triangle(&temp, &groupspaceray, &tris[j]))
{
/*
* Use <= for distance comparsion here so that when there are
* multiple candidates for selection the last block added will
* be selected. It is useful after pasting that the new blocks
* can be dragged to a new location.
*/
if (temp <= nearest->distance)
{
nearest->distance = temp;
nearest->group = group;
nearest->block = block;
nearest->triangle = tris[j];
}
}
}
clear_buffer(buffer);
}
destroy_buffer(buffer);
struct ptrarray *groups = groupdata->groups;
size_t groupcount = ptrarray_count(groups);
for (size_t i = 0; i < groupcount; ++i)
{
struct group *childgroup = get_ptrarray(groups, i);
find_nearest_block(childgroup, ray, nearest);
}
}
/**
* GJK collision support function.
**/
static void
object_support(object_t *a, object_t *b, float direction[3], float out[3])
{
float pa[3];
float pb[3];
object_support_component(a, direction, pa);
vec3_scale(direction, direction, -1);
object_support_component(b, direction, pb);
vec3_subtract(pa, pb, out);
}
void move_group_origin(struct group *group, vec3 const *position)
{
vec3 translation;
vec3_subtract(&translation, &group->position, position);
foreach_block(group->data, translate_block_, &translation);
foreach_group(group->data, translate_group_, &translation);
group->position = *position;
update_group_vertexarray(group);
}
void keyboard(unsigned char key, int x, int y)
{
float direction[3];
float rotation[16];
mat4_identity(rotation);
switch (key) {
case 'q':
vec3_subtract(center, eye, direction);
vec3_normalize(direction, direction);
vec3_add(eye, direction, eye);
break;
case 'e':
vec3_subtract(center, eye, direction);
vec3_normalize(direction, direction);
vec3_subtract(eye, direction, eye);
break;
case 'a':
mat4_rotateY(rotation, 0.1f, rotation);
mat4_multiply(rotation, model, model);
break;
case 'd':
mat4_rotateY(rotation, -0.1f, rotation);
mat4_multiply(rotation, model, model);
break;
case 'w':
mat4_rotateX(rotation, 0.1f, rotation);
mat4_multiply(rotation, model, model);
break;
case 's':
mat4_rotateX(rotation, -0.1f, rotation);
mat4_multiply(rotation, model, model);
break;
case 27:
exit(0);
default:
break;
}
}
bool sphere_possible(vec3 center, float radius, const ray& ray)
{
if(keep_stats) sphere_tests++;
vec3 diff = vec3_subtract(ray.o, center);
float b = 2 * vec3_dot(ray.d, diff);
float radicand = b * b - 4 * (vec3_dot(diff, diff) - radius * radius);
if(radicand < 0)
return false;
return true;
}
/* Manually apply a look-at matrix. Will reset MODELVIEW automatically. */
void cm_apply_look_at(VEC3 target, VEC3 position)
{
VEC3 forward = vec3_normalize(vec3_subtract(target, position));
VEC3 right = vec3_cross(forward, (VEC3){ 0, 1, 0 });
VEC3 up = vec3_normalize(vec3_cross(forward, right));
double ang = atan(NOT_DUMB_ABS(forward.y) / sqrt(forward.x * forward.x + forward.z * forward.z));
if (ang >= PI_O4)
{
up = vec3_negate(up);
}
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
gluLookAt(position.x, position.y, position.z, target.x, target.y, target.z, up.x, up.y, up.z);
}
range sphere_intersect(vec3 center, float radius, const ray& ray)
{
if(keep_stats) sphere_intersections++;
vec3 diff = vec3_subtract(ray.o, center);
float b = 2 * vec3_dot(ray.d, diff);
float radicand = b * b - 4 * (vec3_dot(diff, diff) - radius * radius);
if(radicand < 0)
return range(std::numeric_limits<float>::max(), -std::numeric_limits<float>::max());
float t0 = (-b - sqrtf(radicand)) / 2;
float t1 = (-b + sqrtf(radicand)) / 2;
return range(t0, t1);
}
bool sphere::intersect(const ray& ray, const range& r, surface_hit* hit)
{
float t = sphere_intersect(center, radius, ray, r);
if(t == NO_t)
return false;
if(t > hit->t)
return false;
if(keep_stats) sphere_shadings++;
vec3 point = vec3_add(ray.o, vec3_scale(ray.d, t));
// snap to sphere surface
vec3 to_surface = vec3_subtract(point, center);
float distance = sqrtf(vec3_dot(to_surface, to_surface));
hit->point = vec3_add(center, vec3_scale(to_surface, radius / distance));
hit->normal = vec3_divide(to_surface, radius);
hit->color = color;
hit->t = t;
return true;
}
void matrix_4x4_lookat(math_matrix_4x4 *out,
vec3_t eye,
vec3_t center,
vec3_t up)
{
vec3_t zaxis; /* the "forward" vector */
vec3_t xaxis; /* the "right" vector */
vec3_t yaxis; /* the "up" vector */
vec3_copy(&zaxis[0], center);
vec3_subtract(&zaxis[0], eye);
vec3_normalize(&zaxis[0]);
vec3_cross(&xaxis[0], &zaxis[0], up);
vec3_normalize(&xaxis[0]);
vec3_cross(&yaxis[0], &xaxis[0], zaxis);
MAT_ELEM_4X4(*out, 0, 0) = xaxis[0];
MAT_ELEM_4X4(*out, 0, 1) = yaxis[0];
MAT_ELEM_4X4(*out, 0, 2) = -zaxis[0];
MAT_ELEM_4X4(*out, 0, 3) = 0.0;
MAT_ELEM_4X4(*out, 1, 0) = xaxis[1];
MAT_ELEM_4X4(*out, 1, 1) = yaxis[1];
MAT_ELEM_4X4(*out, 1, 2) = -zaxis[1];
MAT_ELEM_4X4(*out, 1, 3) = 0.0f;
MAT_ELEM_4X4(*out, 2, 0) = xaxis[2];
MAT_ELEM_4X4(*out, 2, 1) = yaxis[2];
MAT_ELEM_4X4(*out, 2, 2) = -zaxis[2];
MAT_ELEM_4X4(*out, 2, 3) = 0.0f;
MAT_ELEM_4X4(*out, 3, 0) = -(xaxis[0] * eye[0] + xaxis[1] * eye[1] + xaxis[2] * eye[2]);
MAT_ELEM_4X4(*out, 3, 1) = -(yaxis[0] * eye[0] + yaxis[1] * eye[1] + yaxis[2] * eye[2]);
MAT_ELEM_4X4(*out, 3, 2) = -(zaxis[0] * eye[0] + zaxis[1] * eye[1] + zaxis[2] * eye[2]);
MAT_ELEM_4X4(*out, 3, 3) = 1.f;
}
/* TODO/FIXME - finish */
void matrix_4x4_lookat(math_matrix_4x4 *out,
vec3_t eye,
vec3_t center,
vec3_t up)
{
vec3_t s, t, f;
vec3_copy(&f[0], center);
vec3_subtract(&f[0], eye);
vec3_normalize(&f[0]);
vec3_cross(&s[0], &f[0], up);
vec3_normalize(&s[0]);
vec3_cross(&t[0], &s[0], f);
memset(out, 0, sizeof(*out));
MAT_ELEM_4X4(*out, 0, 0) = s[0];
MAT_ELEM_4X4(*out, 0, 1) = t[0];
MAT_ELEM_4X4(*out, 0, 2) = -f[0];
MAT_ELEM_4X4(*out, 1, 0) = s[1];
MAT_ELEM_4X4(*out, 1, 1) = t[1];
MAT_ELEM_4X4(*out, 1, 2) = -f[1];
MAT_ELEM_4X4(*out, 2, 0) = s[2];
MAT_ELEM_4X4(*out, 2, 1) = t[2];
MAT_ELEM_4X4(*out, 2, 2) = -f[2];
MAT_ELEM_4X4(*out, 3, 3) = 1.f;
#if 0
mat4x4_translate_in_place(m, -eye[0], -eye[1], -eye[2]);
#endif
}
/**
* Check for collision between objects.
**/
int
object_check_collision(object_t *a, object_t *b)
{
float direction[3] = { 0, 1, 0 };
float simplex[4][3];
size_t simplex_pos = 5;
size_t last;
float middle[3];
float to_last[3];
if (! (object_is_collider(a) &&
object_is_collider(b)))
return 0;
object_support(a, b, direction, simplex[0]);
direction[2] = -1;
object_support(a, b, direction, simplex[1]);
if (vec3_dot(simplex[1], direction) <= 0)
return 0;
vec3_subtract(simplex[1], simplex[0], to_last);
vec3_cross(simplex[1], to_last, direction);
vec3_cross(direction, to_last, direction);
object_support(a, b, direction, simplex[2]);
if (vec3_dot(simplex[2], direction) <= 0)
return 0;
while (vec3_dot(simplex[simplex_pos], direction)) {
if (simplex_pos == 5) {
simplex_pos = 3;
last = 2;
} else {
last = simplex_pos;
simplex_pos =
object_simplex_detect_region(simplex,
simplex_pos);
}
if (simplex_pos == 4)
return 1;
middle[0] = middle[1] = middle[2] = 0;
if (simplex_pos != 3)
vec3_add(simplex[3], middle, middle);
if (simplex_pos != 2)
vec3_add(simplex[2], middle, middle);
if (simplex_pos != 1)
vec3_add(simplex[1], middle, middle);
if (simplex_pos != 0)
vec3_add(simplex[0], middle, middle);
vec3_scale(middle, middle, 1.0/3.0);
vec3_subtract(middle, simplex[last], to_last);
vec3_cross(middle, to_last, direction);
vec3_cross(direction, to_last, direction);
object_support(a, b, direction, simplex[simplex_pos]);
}
return 0;
}
world *load_world(char *fname) // Get world and return pointer.
{
char *inpstr;
int wkd;
std::auto_ptr<world> w(new world);
time_t prev = time(NULL);
scoped_FILE fp(fopen(fname, "r"));
if(fp == NULL) {
fprintf(stderr, "Cannot open file %s for input.\nE#%d\n", fname, errno);
return NULL;
}
if((inpstr = getstr(fp)) == NULL) {
fprintf(stderr, "Cannot read title.\n");
return NULL;
}
if(strcmp(inpstr, ".") != 0) {
w->Title = NULL;
} else {
w->Title = new char[strlen(inpstr) + 1];
strcpy(w->Title, inpstr);
}
// lace now ignored
int lace;
if(!getint(fp, &lace)) {
fprintf(stderr, "*!LACE\n");
return NULL;
}
int wdth, lnth; // now ignored
if(!getint(fp, &wdth)) {
fprintf(stderr, "*!WDTH\n");
return NULL;
}
if(!getint(fp, &lnth)) {
fprintf(stderr, "*!LNTH\n");
return NULL;
}
int xsub, ysub; // now ignored
if(!getint(fp, &xsub)) {
fprintf(stderr, "*!xsub\n");
return NULL;
}
if(!getint(fp, &ysub)) {
fprintf(stderr, "*!ysub\n");
return NULL;
}
w->xsub = 1;
w->ysub = 1;
int r, g, b, brt;
if(!getint(fp, &r)) {
fprintf(stderr, "*!backgroundr\n");
return NULL;
}
if(!getint(fp, &g)) {
fprintf(stderr, "*!backgroundg\n");
return NULL;
}
if(!getint(fp, &b)) {
fprintf(stderr, "*!backgroundb\n");
return NULL;
}
if(!getint(fp, &brt)) {
fprintf(stderr, "*!backgroundb\n");
return NULL;
}
w->background.x = r / 16.0 * brt / 100.0;
w->background.y = g / 16.0 * brt / 100.0;
w->background.z = b / 16.0 * brt / 100.0;
int df;
if(!getint(fp, &df)) {
fprintf(stderr, "*!DIFFUSION\n");
return NULL;
}
if(!getint(fp, &w->sphere_count)) {
fprintf(stderr, "*!#Sphere\n");
return NULL;
}
prev = time(NULL);
w->spheres = new sphere[w->sphere_count];
for(int i = 0; i < w->sphere_count; i++) {
if(time(NULL) > prev) {
prev = time(NULL);
fprintf(stderr, "loaded %u spheres\n", i);
}
float x, y, z, radius;
wkd = fltget(fp, &x) && fltget(fp, &y);
wkd = (wkd && fltget(fp, &z) && fltget(fp, &radius));
int r, g, b, brt;
wkd = (wkd && getint(fp, &r) && getint(fp, &g));
wkd = (wkd && getint(fp, &b) && getint(fp, &brt));
if(!wkd) {
fprintf(stderr, "*!Sphere #%d\n", i);
return NULL;
}
vec3 color(r / 16.0 * brt / 100.0,
g / 16.0 * brt / 100.0, b / 16.0 * brt / 100.0);
w->spheres[i] = sphere(vec3(x, y, z), radius, color);
}
w->scene_center = w->spheres[0].center;
for(int i = 1; i < w->sphere_count; i++) {
w->scene_center = vec3_add(w->spheres[i].center, w->scene_center);
}
w->scene_center = vec3_divide(w->scene_center, w->sphere_count);
w->scene_extent = 0;
for(int i = 0; i < w->sphere_count; i++) {
vec3 to_center = vec3_subtract(w->scene_center, w->spheres[i].center);
float distance = sqrtf(vec3_dot(to_center, to_center)) + w->spheres[i].radius;
w->scene_extent = std::max(w->scene_extent, distance);
}
w->scene_extent *= 2;
w->root = make_tree(w->spheres, 0, w->sphere_count);
print_tree_stats();
wkd = fltget(fp, &w->cam.eye.x) && fltget(fp, &w->cam.eye.y);
wkd = (wkd && fltget(fp, &w->cam.eye.z) && fltget(fp, &w->cam.yaw));
wkd = (wkd && fltget(fp, &w->cam.pitch) && fltget(fp, &w->cam.roll));
wkd = (wkd && fltget(fp, &w->cam.fov));
if(!wkd) {
fprintf(stderr, "*!Viewpoint\n");
return NULL;
}
w->cam.pitch = to_radians(w->cam.pitch);
w->cam.yaw = to_radians(w->cam.yaw);
w->cam.roll = to_radians(w->cam.roll);
w->cam.fov = to_radians(w->cam.fov);
return w.release();
}
group* make_tree(sphere* spheres, int start, unsigned int count, int level = 0)
{
if(level == 0) {
previous = time(NULL);
if(getenv("DEBUG_BVH") != NULL) {
bvh_spheres_debug_output = fopen("bvh.r9", "w");
}
}
if(time(NULL) > previous) {
fprintf(stderr, "total treed = %d\n", total_treed);
previous = time(NULL);
}
if((level >= bvh_max_depth) || count <= bvh_leaf_max) {
total_treed += count;
group* g = new group(spheres, start, count);
if(bvh_spheres_debug_output != NULL) {
// fprintf(bvh_spheres_debug_output, "sphere 7 %f %f %f %f 1 1 1 # %d\n", g->radius, g->center.x, g->center.y, g->center.z, level );
if(level == 0) {
fclose(bvh_spheres_debug_output);
bvh_spheres_debug_output = NULL;
}
}
bvh_leaf_size_counts[std::min(63U, count)]++;
bvh_leaf_count++;
bvh_level_counts[level]++;
bvh_node_count++;
return g;
}
vec3 split_pivot;
vec3 split_plane_normal;
// find bounding box
vec3 boxmin, boxmax;
box_init(boxmin, boxmax);
for(unsigned int i = 0; i < count; i++) {
sphere &s = spheres[start + i];
vec3 spheremin = vec3_subtract(s.center, vec3(s.radius));
vec3 spheremax = vec3_add(s.center, vec3(s.radius));
box_extend(boxmin, boxmax, spheremin, spheremax);
}
split_pivot = vec3_scale(vec3_add(boxmin, boxmax), .5);
vec3 boxdim = vec3_subtract(boxmax, boxmin);
if(boxdim.x > boxdim.y && boxdim.x > boxdim.z) {
split_plane_normal = vec3(1, 0, 0);
} else if(boxdim.y > boxdim.z) {
split_plane_normal = vec3(0, 1, 0);
} else {
split_plane_normal = vec3(0, 0, 1);
}
// XXX output split plane to BVH debug file
int startA;
int countA;
int startB;
int countB;
if(!bvh_split_median) {
int s1 = start - 1;
int s2 = start + count;
do {
// from start to s1, not including s1, is negative
// from s2 to start + count - 1 is positive
do {
s1 += 1;
} while((s1 < s2) && vec3_dot(vec3_subtract(spheres[s1].center, split_pivot), split_plane_normal) < 0);
// If there wasn't a positive sphere before s2, done.
if(s1 >= s2)
break;
// s1 is now location of lowest positive sphere
do {
s2 -= 1;
} while((s1 < s2) && vec3_dot(vec3_subtract(spheres[s2].center, split_pivot), split_plane_normal) >= 0);
// If there wasn't a negative sphere between s1 and s2, done
if(s1 >= s2)
break;
// s2 is now location of highest negative sphere
std::swap(spheres[s1], spheres[s2]);
} while(true);
// s1 is the first of the positive spheres
startA = start;
countA = s1 - startA;
startB = s1;
countB = start + count - s1;
} else {
sphere_sorter sorter(split_plane_normal);
std::sort(spheres + start, spheres + start + count - 1, sorter);
startA = start;
countA = count / 2;
startB = startA + countA;
countB = count - countA;
}
group *g;
if(countA > 0 && countB > 0) {
// get a tighter bound around children than hierarchical bounds
vec3 boxmin, boxmax;
box_init(boxmin, boxmax);
for(unsigned int i = 0; i < count; i++) {
add_sphere(&boxmin, &boxmax, spheres[start + i].center, spheres[start + i].radius);
}
// construct children
group *g1 = make_tree(spheres, startA, countA, level + 1);
g = new group(spheres, g1, NULL, split_plane_normal, boxmin, boxmax);
group *g2 = make_tree(spheres, startB, countB, level + 1);
g->positive = g2;
bvh_level_counts[level]++;
bvh_node_count++;
} else {
total_treed += count;
fprintf(stderr, "Leaf node at %d, %u spheres, total %d\n", level, count, total_treed);
g = new group(spheres, start, count);
bvh_leaf_size_counts[std::min(63U, count)]++;
bvh_leaf_count++;
bvh_level_counts[level]++;
bvh_node_count++;
}
if(bvh_spheres_debug_output != NULL) {
// fprintf(bvh_spheres_debug_output, "sphere 7 %f %f %f %f 1 1 1 # %d\n", g->radius, g->center.x, g->center.y, g->center.z, level );
if(level == 0) {
fclose(bvh_spheres_debug_output);
bvh_spheres_debug_output = NULL;
}
}
return g;
}
bool operator() (const sphere& s1, const sphere& s2)
{
vec3 diff = vec3_subtract(s2.center, s1.center);
return vec3_dot(diff, split_plane_normal) > 0;
}
